1. Field of the Invention
The present invention relates to a temperature measuring system, a substrate processing apparatus, and a temperature measuring method.
2. Description of the Related Art
Patent Reference 1 discloses a kind of temperature measuring system. The temperature measuring system disclosed in Patent Reference 1 includes a light source, a splitter, a mirror, a driving unit, and a light receiving unit. Light emitted from the light source is split into measuring light and reference light by the splitter. The measuring light is reflected respectively by opposite end surfaces of an object to be measured, and then reaches the light receiving unit via the splitter. Meanwhile, the reference light is reflected by the mirror, and reaches the light receiving unit via the splitter. The mirror is moved by the driving unit, and when a distance from the splitter to the mirror becomes the same as a distance from the splitter to an end surface of the object to be measured, interference peaks occur. A distance between two interference peaks becomes a length of an optical path between the opposite end surfaces of the object to be measured. A temperature of the object to be measured may be measured from the obtained optical path length.
When measuring the temperature, it is desirable that the temperature is measured with high sampling rate. However, according to the above described apparatus, a sampling rate is dependent upon a driving time of the mirror, and thus, in order to obtain the high sampling rate, a driving unit of the mirror has to be driven at a high speed. Meanwhile, in order to realize the high sampling rate, a method of defining a thickness of an object to be measured based on intensities of light reflected by a surface and a rear surface of the object to be measured can be suggested. However, in order to detect temperature variation appropriately by using the above method, a thickness has to be measured with high accuracy.
Thus, in the present technology field, a temperature measuring apparatus capable of measuring a temperature of an object to be measured appropriately by using optical interference, a substrate processing apparatus, and a temperature measuring method are necessary.
3. Prior Art Reference    (Patent Reference 1) Japanese Laid-open Patent Publication No. 2006-220461